کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2025039 1069976 2011 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The magnitude and variability of soil-surface CO2 efflux increase with mean annual temperature in Hawaiian tropical montane wet forests
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش خاک شناسی
پیش نمایش صفحه اول مقاله
The magnitude and variability of soil-surface CO2 efflux increase with mean annual temperature in Hawaiian tropical montane wet forests
چکیده انگلیسی

Soil-surface CO2 efflux (FS; ‘soil respiration’) accounts for ≥50% of the CO2 released annually by the terrestrial biosphere to the atmosphere, and the magnitude and variability of this flux are likely to be sensitive to climate change. We measured FS in nine permanent plots along a 5.2 °C mean annual temperature (MAT) gradient (13–18.2 °C) in Hawaiian tropical montane wet forests where substrate type and age, soil type, soil water balance, disturbance history, and canopy vegetation are constant. The objectives of this study were to quantify how the (i) magnitude, (ii) plot-level spatial variability, and (iii) plot-level diel variability of FS vary with MAT. To address the first objective, annual FS budgets were constructed by measuring instantaneous FS monthly in all plots for one year. For the second objective, we compared plot-level mean instantaneous FS in six plots derived from 8 versus 16 measurements, and conducted a power analysis to determine adequate sample sizes. For the third objective, we measured instantaneous FS hourly for 24 h in three plots (cool, intermediate and warm MATs). The magnitude of annual FS and the spatial variability of plot-level instantaneous FS increased linearly with MAT, likely due to concomitant increases in stand productivity. Mean plot-level instantaneous FS from 8 versus 16 measurements per plot yielded statistically similar patterns. The number of samples required to estimate plot-level instantaneous FS within 10% and 20% of the actual mean increased with MAT. In two of three plots examined, diel variability in instantaneous FS was significantly correlated with soil temperature but minimal diel fluctuations in soil temperature (<0.6 °C) resulted in minimal diel variability in FS. Our results suggest that as MAT increases in tropical montane wet forests, FS will increase and become more spatially variable if ecosystem characteristics and functioning undergo concurrent changes as measured along this gradient. However, diel variation in FS will remain a minor component of overall plot-level variation.


► FS increases linearly with MAT in tropical montane wet forests.
► Increased FS is likely due to concomitant increases in stand productivity with MAT.
► Within-plot spatial variability of instantaneous FS increases with MAT.
► More measurements will be needed to accurately estimate plot-level FS with warming.
► Within-plot diel variability in FS is minimal in tropical montane wet forests.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Soil Biology and Biochemistry - Volume 43, Issue 11, November 2011, Pages 2315–2323
نویسندگان
, , , , ,